android4.0蓝牙使能的详细解析

内容简介：本文详细分析了android4.0 中蓝牙使能的过程，相比较android2.3，4.0中的蓝牙最大的差别在于UI上on/off的伪开关。在android4.0中加入了 adapter的状态机。所谓的状态机就类似于状态转换图，在一个状态收到某个特定的命令会变成另外一个状态，不同的命令可以跳转到不同的状态（当然也有 可能到同一状态）。adapter的初始状态为poweroff，在android系统启动的时候会进入warmup状态，同时会进行UUID的add， 该操作会引起propertychanged的UUID signal，该signal会使得状态从warmup变换到hotoff状态。因此在UI端off时其实adapter已经处于hotoff状态而不是 poweroff状态。这一点是很关键的。在正文中，我会从假如我不知道这些开始来描绘整个使能的过程。

正文：

毫无疑问，bluetooth的打开是在Settings中进行的操作。因此，冤有头，债有主，我们来到了Settings.java中，果然发现了相关的代码如下：

mBluetoothEnabler =new BluetoothEnabler(context, new Switch(context));

于是，我们得以进入真正的蓝牙操作的殿堂，好好进去看看吧。

1、BluetoothEnabler的构造函数             public BluetoothEnabler(Context context,Switch switch_) {            mContext = context;            mSwitch = switch_;    //很简单了，去调用一个LocalBluetoothManager类的getInstance，其实会构造该类的            LocalBluetoothManager manager =LocalBluetoothManager.getInstance(context);            if (manager == null) {                // Bluetooth is not supported                mLocalAdapter = null;                mSwitch.setEnabled(false);            } else {    //构造成功后，通过manager得到bluetooth的adapter                mLocalAdapter =manager.getBluetoothAdapter();            }    //同时新建一个intent，用于接收ACTION_STATE_CHANGED            mIntentFilter = newIntentFilter(BluetoothAdapter.ACTION_STATE_CHANGED);        }         2、LocalBluetoothManager类的getInstance        public static synchronizedLocalBluetoothManager getInstance(Context context) {            if (sInstance == null) {    //2.1同样的，这个会去调用LocalBluetoothAdapter的getInstance，也会构造该类                LocalBluetoothAdapter adapter =LocalBluetoothAdapter.getInstance();                if (adapter == null) {                    return null;                }                // This will be around as long asthis process is                Context appContext =context.getApplicationContext();    //2.2构造LocalBluetoothManager类                sInstance = newLocalBluetoothManager(adapter, appContext);            }                 return sInstance;        }    2.1LocalBluetoothAdapter的getInstance             static synchronized LocalBluetoothAdaptergetInstance() {            if (sInstance == null) {    //2.1.1通过BluetoothAdapter得到DefaultAdapter                BluetoothAdapter adapter =BluetoothAdapter.getDefaultAdapter();                if (adapter != null) {    //2.1.2若有该DefaultAdapter，则构造LocalBluetoothAdapter                    sInstance = newLocalBluetoothAdapter(adapter);                }            }                 return sInstance;        }         2.1.1BluetoothAdapter得到DefaultAdapter             public static synchronized BluetoothAdaptergetDefaultAdapter() {            if (sAdapter == null) {                IBinder b =ServiceManager.getService(BluetoothAdapter.BLUETOOTH_SERVICE);                if (b != null) {                    IBluetooth service =IBluetooth.Stub.asInterface(b);                    sAdapter = newBluetoothAdapter(service);                }            }            return sAdapter;        }         2.1.2构造LocalBluetoothAdapter    //其实就是 mAdapter的初始化而已        privateLocalBluetoothAdapter(BluetoothAdapter adapter) {            mAdapter = adapter;        }    2.2构造LocalBluetoothManager类    //管理本地蓝牙类，用来在蓝牙API子类上面再封装一个接口        privateLocalBluetoothManager(LocalBluetoothAdapter adapter, Context context) {            mContext = context;    //mLocalAdapter初始化为DefaultAdapter中得到的值    mLocalAdapter= adapter;    //构造CachedBluetoothDeviceManager，用来管理远程蓝牙设备            mCachedDeviceManager = newCachedBluetoothDeviceManager(context);    //2.2.1构建BluetoothEventManager，该类是用来管理广播消息和回调函数的，即分发不同的消息去对UI进行处理            mEventManager = newBluetoothEventManager(mLocalAdapter,                    mCachedDeviceManager, context);    //2.2.2该类提供对不同LocalBluetoothProfile object的访问            mProfileManager = newLocalBluetoothProfileManager(context,                    mLocalAdapter,mCachedDeviceManager, mEventManager);        }         2.2.1构建BluetoothEventManager             BluetoothEventManager(LocalBluetoothAdapteradapter,                CachedBluetoothDeviceManagerdeviceManager, Context context) {            mLocalAdapter = adapter;            mDeviceManager = deviceManager;    //创建两个IntentFilter            mAdapterIntentFilter = newIntentFilter();    //这里没有对mProfileIntentFilter进行初始化，这个在LocalBluetoothProfileManager的addProfile中实现            mProfileIntentFilter = newIntentFilter();    //创建一个Handler的Hash表            mHandlerMap = new HashMap<String,Handler>();            mContext = context;         //注册对adapter和Device的几个广播消息的处理回调函数    //add action到mAdapterIntentFilter            // Bluetooth on/off broadcasts           addHandler(BluetoothAdapter.ACTION_STATE_CHANGED, newAdapterStateChangedHandler());                 // Discovery broadcasts           addHandler(BluetoothAdapter.ACTION_DISCOVERY_STARTED, newScanningStateChangedHandler(true));           addHandler(BluetoothAdapter.ACTION_DISCOVERY_FINISHED, newScanningStateChangedHandler(false));           addHandler(BluetoothDevice.ACTION_FOUND, new DeviceFoundHandler());           addHandler(BluetoothDevice.ACTION_DISAPPEARED, newDeviceDisappearedHandler());           addHandler(BluetoothDevice.ACTION_NAME_CHANGED, newNameChangedHandler());                 // Pairing broadcasts           addHandler(BluetoothDevice.ACTION_BOND_STATE_CHANGED, newBondStateChangedHandler());           addHandler(BluetoothDevice.ACTION_PAIRING_CANCEL, newPairingCancelHandler());                 // Fine-grained state broadcasts           addHandler(BluetoothDevice.ACTION_CLASS_CHANGED, newClassChangedHandler());            addHandler(BluetoothDevice.ACTION_UUID,new UuidChangedHandler());                 // Dock event broadcasts            addHandler(Intent.ACTION_DOCK_EVENT,new DockEventHandler());    //mAdapterIntentFilter的接收处理函数           mContext.registerReceiver(mBroadcastReceiver, mAdapterIntentFilter);        }         2.2.2构造LocalBluetoothProfileManager类             LocalBluetoothProfileManager(Contextcontext,                LocalBluetoothAdapter adapter,                CachedBluetoothDeviceManagerdeviceManager,                BluetoothEventManager eventManager){            mContext = context;         //各个类之间进行关联            mLocalAdapter = adapter;            mDeviceManager = deviceManager;            mEventManager = eventManager;            // pass this reference to adapter andevent manager (circular dependency)            mLocalAdapter.setProfileManager(this);            mEventManager.setProfileManager(this);                 ParcelUuid[] uuids =adapter.getUuids();                 // uuids may be null if Bluetooth isturned off            if (uuids != null) {    //假如已经有了uuid，根据uuid来add并new对应的profile，只针对A2DP,HFP,HSP,OPP四个profile，HID和PAN在下面，每次都add                updateLocalProfiles(uuids);            }                 // Always add HID and PAN profiles    //加入HID和PAN两个profile            mHidProfile = new HidProfile(context,mLocalAdapter);            addProfile(mHidProfile,HidProfile.NAME,                   BluetoothInputDevice.ACTION_CONNECTION_STATE_CHANGED);                 mPanProfile = new PanProfile(context);            addPanProfile(mPanProfile,PanProfile.NAME,                   BluetoothPan.ACTION_CONNECTION_STATE_CHANGED);                 Log.d(TAG,"LocalBluetoothProfileManager construction complete");        }         好吧，其实我们被骗了，刚刚只是一个路引，不是真正的操作，真正的操作向来都是从你滑动界面那个on/off键开始的，因此我们决定把这个键的处理给揪出来。在Settings界面上一共就只有两个on/off键，一个是wifi，另一个就是蓝牙了，我们从这个代码入手：                    case HEADER_TYPE_SWITCH:    //其实写这个代码的人也比较心虚，假如switch多一点，下面就要重写了                        // Would need a differenttreatment if the main menu had more switches                        if (header.id ==R.id.wifi_settings) {                           mWifiEnabler.setSwitch(holder.switch_);                        } else {    //这个就是处理了，上面的路引没有白做啊                           mBluetoothEnabler.setSwitch(holder.switch_);                        }         3、mBluetoothEnabler.setSwitch分析             public void setSwitch(Switch switch_) {    //若是和上次相同，则不做任何事情，可以理解，代码也懒嘛            if (mSwitch == switch_) return;    //把上次的switch的changelistener清空           mSwitch.setOnCheckedChangeListener(null);            mSwitch = switch_;    //重设这次的switch的changelistener           mSwitch.setOnCheckedChangeListener(this);                 int bluetoothState =BluetoothAdapter.STATE_OFF;    //获取getBluetoothState，这个过程也会同步一下state，防止改变            if (mLocalAdapter != null)bluetoothState = mLocalAdapter.getBluetoothState();    //根据状态设置一下两个标志位            boolean isOn = bluetoothState ==BluetoothAdapter.STATE_ON;            boolean isOff = bluetoothState ==BluetoothAdapter.STATE_OFF;    //设置checked的状态位。注意，假如这里状态发生了改变，则会调用this.onCheckedChanged来进行处理            mSwitch.setChecked(isOn);            if(WirelessSettings.isRadioAllowed(mContext, Settings.System.RADIO_BLUETOOTH)) {    //有bluetooth或者不是airplane，则该switch不变灰，否则，灰的。                mSwitch.setEnabled(isOn || isOff);            } else {                mSwitch.setEnabled(false);            }        }         4、onCheckedChanged    在switch状态发生改变后，会调用这个地方的回调函数进行处理。             public void onCheckedChanged(CompoundButtonbuttonView, boolean isChecked) {            // Show toast message if Bluetooth isnot allowed in airplane mode    //若是打开的话，就需要检查一下是否allow Bluetooth（radio，airplane的check）            if (isChecked &&                   !WirelessSettings.isRadioAllowed(mContext,Settings.System.RADIO_BLUETOOTH)) {                Toast.makeText(mContext,R.string.wifi_in_airplane_mode, Toast.LENGTH_SHORT).show();                // Reset switch to off    //若是不对的话，reset为off                buttonView.setChecked(false);            }                 if (mLocalAdapter != null) {    //4.1设置scanmode，放心，它会判断state的，不是STATE_ON，会直接返回false的               mLocalAdapter.setScanMode(BluetoothAdapter.SCAN_MODE_CONNECTABLE);    //4.2使能或不使能Bluetooth了               mLocalAdapter.setBluetoothEnabled(isChecked);            }    //过程中还是会反灰，直到setBluetoothEnabled的结果返回会改变switch的状态            mSwitch.setEnabled(false);        }         4.1设置scanmod         会调用adapter中的setScanMode，直接去看就可以了，事实上就是设置了两个property标志，没什么             public boolean setScanMode(int mode) {    //这里把这个代码写出来就是证明一下，STATE_ON才会真正做下去，否则免谈            if (getState() != STATE_ON) returnfalse;    //这里会调用对应server中的setScanMode            return setScanMode(mode, 120);        }             public synchronized boolean setScanMode(intmode, int duration) {    //这里有个permission，好像和2.3中不一样，注意一下     mContext.enforceCallingOrSelfPermission(android.Manifest.permission.WRITE_SECURE_SETTINGS,    "NeedWRITE_SECURE_SETTINGS permission");            boolean pairable;            boolean discoverable;                 switch (mode) {            case BluetoothAdapter.SCAN_MODE_NONE:                pairable = false;                discoverable = false;                break;            caseBluetoothAdapter.SCAN_MODE_CONNECTABLE:    //开始就是这里了，可pairable，但是不可discoverable                pairable = true;                discoverable = false;                break;            caseBluetoothAdapter.SCAN_MODE_CONNECTABLE_DISCOVERABLE:                pairable = true;                discoverable = true;                if (DBG) Log.d(TAG, "BTDiscoverable for " + duration + " seconds");                break;            default:                Log.w(TAG, "Requested invalidscan mode " + mode);                return false;            }         //设置这两个property标志           setPropertyBoolean("Discoverable", discoverable);           setPropertyBoolean("Pairable", pairable);            return true;        }         4.2setBluetoothEnabled分析             public void setBluetoothEnabled(booleanenabled) {    //根据enabled的标志设置是enable还是disable，在2.3中，这个地方就是bt_enable哦，这里还不知道，我们在第5步进行详细的分析            boolean success = enabled                    ? mAdapter.enable()                    : mAdapter.disable();    //成功了，设置对应的状态位            if (success) {                setBluetoothStateInt(enabled                    ?BluetoothAdapter.STATE_TURNING_ON                    :BluetoothAdapter.STATE_TURNING_OFF);            } else {                if (Utils.V) {                    Log.v(TAG,"setBluetoothEnabled call, manager didn't return " +                            "success forenabled: " + enabled);                }    //同步一下设置的状态                syncBluetoothState();            }        }    }         5、mAdapter.enable或者mAdapter.disable         就先分析enable吧，它会调用对应server端的enable(ture),我们来看看源码             public synchronized boolean enable(booleansaveSetting) {           mContext.enforceCallingOrSelfPermission(BLUETOOTH_ADMIN_PERM,                                                   "Need BLUETOOTH_ADMIN permission");                 // Airplane mode can prevent Bluetoothradio from being turned on.    //检查是否是飞行模式            if (mIsAirplaneSensitive &&isAirplaneModeOn() && !mIsAirplaneToggleable) {                return false;            }    //5.1注意与2.3的不同，在2.3中，这里会调用enablethread去调用native的bt_enable，而4.0没有这么做。没事，我们来分析4.0怎么做的。           mBluetoothState.sendMessage(BluetoothAdapterStateMachine.USER_TURN_ON,saveSetting);            return true;        }         5.1mBluetoothState.sendMessage         简单理解一下，mBluetoothState是BluetoothAdapterStateMachine类。因此，在分析的之前，简单说一下，它其实就是类似一个状态转换图，根据你所处于的状态，然后再判断收到的操作，进行不同的处理。根据构造函数中的setInitialState(mPowerOff);可以知道初始状态是PowerOff。但是从它给出的状态机可以看出，在PowerOff的状态时，它是通过TURN_HOT/TURN_ON来改变到HotOff状态的，然后才会收到USER_TURN_ON，去该变到BluetootOn的状态。因此，可以肯定的是我们这里的USER_TURN_ON不是它收到的第一个message，因此我们去纠结一下它是从哪里开始改变PowerOff的状态：extra1，然后再来看这里的处理吧：5.2。         extra1、mAdapter.enable之前的状态机转变         众所周知，android在启动之后会启动一个serverThread的线程，通过这个线程会启动一系列的服务。我们的蓝牙服务也是在这里启动的，android4.0其实在这个地方对状态机进行了修改，我们来看一下源码：    该代码位于framworks/base/services/java/com/android/server/systemserver.java    BluetoothServicebluetooth = null;    BluetoothA2dpServicebluetoothA2dp = null;         //模拟器上是不支持Bluetooth的，工厂测试模式也没有Bluetooth（这个不了解）                // Skip Bluetooth if we have anemulator kernel                // TODO: Use a more reliable checkto see if this product should                // support Bluetooth - see bug988521                if(SystemProperties.get("ro.kernel.qemu").equals("1")) {                    Slog.i(TAG, "No BluetoohService (emulator)");                } else if (factoryTest ==SystemServer.FACTORY_TEST_LOW_LEVEL) {                    Slog.i(TAG, "No BluetoothService (factory test)");                } else {                    Slog.i(TAG, "BluetoothService");    //新建Bluetoothservice，并把他加入到ServiceManager中                    bluetooth = newBluetoothService(context);                   ServiceManager.addService(BluetoothAdapter.BLUETOOTH_SERVICE,bluetooth);    //extra1.1在启动Bluetooth服务后进行一些初始化，呵呵，这里就对状态机进行了改变                   bluetooth.initAfterRegistration();         //新建了BluetoothA2dpService，并把之加入到了ServiceManager中    bluetoothA2dp= new BluetoothA2dpService(context, bluetooth);                   ServiceManager.addService(BluetoothA2dpService.BLUETOOTH_A2DP_SERVICE,                                             bluetoothA2dp);    //extra1.2同样的要在之后做些init的工作                   bluetooth.initAfterA2dpRegistration();    //得到是否飞行                    int airplaneModeOn =Settings.System.getInt(mContentResolver,                           Settings.System.AIRPLANE_MODE_ON, 0);    //看Bluetooth是否on，若是打开的状态（没有飞行），则这里会调用enable去打开                    int bluetoothOn =Settings.Secure.getInt(mContentResolver,                       Settings.Secure.BLUETOOTH_ON, 0);                    if (airplaneModeOn == 0&& bluetoothOn != 0) {                        bluetooth.enable();                    }                }         extra1.1initAfterRegistration分析             public synchronized voidinitAfterRegistration() {    //得到default的adapter            mAdapter =BluetoothAdapter.getDefaultAdapter();    //创建BluetoothAdapterStateMachine，初始化几个状态，并设初始状态位POWEROFF,这里同时新建了一个EventLoop            mBluetoothState = newBluetoothAdapterStateMachine(mContext, this, mAdapter);            mBluetoothState.start();    //根据这个xml的bool变量来决定是否先期TURN_HOT，该变量位于frameworks/base/core/res/res/values/config.xml中，默认为true            if (mContext.getResources().getBoolean               (com.android.internal.R.bool.config_bluetooth_adapter_quick_switch)) {    //extra1.2发送TURN_HOT的状态变化message               mBluetoothState.sendMessage(BluetoothAdapterStateMachine.TURN_HOT);            }    //得到对应的EventLoop            mEventLoop =mBluetoothState.getBluetoothEventLoop();        }         extra1.2  TURN_HOT message的处理             /**         * Bluetooth module's power is off,firmware is not loaded.         */        private class PowerOff extends State {            @Override            public void enter() {                if (DBG) log("Enter PowerOff:" + getCurrentMessage().what);            }            @Override            public boolean processMessage(Messagemessage) {                log("PowerOff process message:" + message.what);                     boolean retValue = HANDLED;                switch(message.what) {    ……                   case TURN_HOT:    //extra1.3这里就是我们寻找了千年的bt_enable所在的地方。我们去看看                        if (prepareBluetooth()) {    //extra1.5转变状态到warmup，在prepareBluetooth真正完成后，这个状态还会发生改变                            transitionTo(mWarmUp);                        }                        break;    ……         extra1.3prepareBluetooth分析         看英文注释就知道了，不解释            /**             * Turn on Bluetooth Module, Loadfirmware, and do all the preparation             * needed to get the Bluetooth Moduleready but keep it not discoverable             * and not connectable.             * The last step of this method sets upthe local service record DB.             * There will be a event reporting thestatus of the SDP setup.             */            private boolean prepareBluetooth() {    //extra1.4首先还是调用了enableNative的本地方法，到这里你会发现终于和2.3相似了（不过请注意调用的时机不同了，这个在初始化，而2.3在界面的on/off滑动的时候），它还是会调用bt_enable，这个就会调用对应的set_bluetooth_power了                if(mBluetoothService.enableNative() != 0) {                    return false;                }                     // try to start event loop, give 2attempts    //尝试两次去start event loop                int retryCount = 2;                boolean eventLoopStarted = false;                while ((retryCount-- > 0)&& !eventLoopStarted) {                    mEventLoop.start();                    // it may take a moment for theother thread to do its                    // thing.  Check periodically for a while.                    int pollCount = 5;                    while ((pollCount-- > 0)&& !eventLoopStarted) {                        if(mEventLoop.isEventLoopRunning()) {                            eventLoopStarted =true;                            break;                        }                        try {                            Thread.sleep(100);                        } catch(InterruptedException e) {                           log("prepareBluetooth sleep interrupted: " + pollCount);                            break;                        }                    }                }    //出错处理                if (!eventLoopStarted) {                   mBluetoothService.disableNative();                    return false;                }                     // get BluetoothService ready    //建立native data以及SDP相关的一些操作，这里将会产生PropertyChanged的UUIDs的signal，对该信号的处理会对状态发生改变，详细分析见extra1.5                if(!mBluetoothService.prepareBluetooth()) {                    mEventLoop.stop();                   mBluetoothService.disableNative();                    return false;                }    //设置一个prepare的超时处理，在该时间内没有收到UUID changed的signal将会进行错误处理               sendMessageDelayed(PREPARE_BLUETOOTH_TIMEOUT,PREPARE_BLUETOOTH_TIMEOUT_TIME);                return true;            }        }         extra1.4bt_enable分析         intbt_enable() {        LOGV(__FUNCTION__);             int ret = -1;        int hci_sock = -1;        int attempt;         //power的设置，on。不解释，可加入对应板子的gpio口的处理，默认就只用了rfkill的处理        if (set_bluetooth_power(1) < 0) gotoout;    //开始hciattach服务，这个我们也做了修改，加入了rtk_h5        LOGI("Starting hciattachdaemon");        if (property_set("ctl.start","hciattach") < 0) {            LOGE("Failed to starthciattach");            set_bluetooth_power(0);            goto out;        }                  // Try for 10 seconds, this can onlysucceed once hciattach has sent the        // firmware and then turned on hci devicevia HCIUARTSETPROTO ioctl        for (attempt = 1000; attempt > 0;  attempt--) {    //创建hci_sock            hci_sock = create_hci_sock();            if (hci_sock < 0) goto out;    //调用ioctl的HCIDEVUP，来判断hciattach是否已经ok了。            ret = ioctl(hci_sock, HCIDEVUP,HCI_DEV_ID);                 LOGI("bt_enable: ret: %d, errno:%d", ret, errno);            if (!ret) {                break;            } else if (errno == EALREADY) {                LOGW("Bluetoothd alreadystarted, unexpectedly!");                break;            }                 close(hci_sock);    //等待10 ms后再试一次            usleep(100000);  // 100 ms retry delay        }    //10s都没有搞定，需要做个失败的处理        if (attempt == 0) {            LOGE("%s: Timeout waiting for HCIdevice to come up, error- %d, ",                __FUNCTION__, ret);            if (property_set("ctl.stop","hciattach") < 0) {                LOGE("Error stoppinghciattach");            }            set_bluetooth_power(0);            goto out;        }    //启动bluetoothd服务        LOGI("Starting bluetoothddeamon");        if (property_set("ctl.start","bluetoothd") < 0) {            LOGE("Failed to startbluetoothd");            set_bluetooth_power(0);            goto out;        }             ret = 0;         out:    //关闭hci_sock        if (hci_sock >= 0) close(hci_sock);        return ret;    }         extra 1.5 PropetyChanged的UUIDs的处理         event_filter是用来对bluez的dbus的signal进行监听的，有signal产生后，会在这里进行处理。因此，我们直接到这里看看该怎么处理。         //Called by dbus during WaitForAndDispatchEventNative()    staticDBusHandlerResult event_filter(DBusConnection *conn, DBusMessage *msg,                                          void*data) {        native_data_t *nat;        JNIEnv *env;        DBusError err;        DBusHandlerResult ret;         //err的一个初始化        dbus_error_init(&err);    //得到参数        nat = (native_data_t *)data;        nat->vm->GetEnv((void**)&env,nat->envVer);        if (dbus_message_get_type(msg) !=DBUS_MESSAGE_TYPE_SIGNAL) {            LOGV("%s: not interested (not asignal).", __FUNCTION__);            returnDBUS_HANDLER_RESULT_NOT_YET_HANDLED;        }             LOGV("%s: Received signal %s:%s from%s", __FUNCTION__,            dbus_message_get_interface(msg),dbus_message_get_member(msg),            dbus_message_get_path(msg));             env->PushLocalFrame(EVENT_LOOP_REFS);    ……    //PropertyChanged这个signal的处理        } else if (dbus_message_is_signal(msg,                                         "org.bluez.Adapter",                                         "PropertyChanged")) {    //由msg解析参数            jobjectArray str_array =parse_adapter_property_change(env, msg);            if (str_array != NULL) {                /* Check if bluetoothd has(re)started, if so update the path. */                jstring property =(jstring)env->GetObjectArrayElement(str_array, 0);                const char *c_property =env->GetStringUTFChars(property, NULL);    //检查Property是否started                if (!strncmp(c_property,"Powered", strlen("Powered"))) {    //若是powered，则看value是否是true，是ture就得到对应的path                    jstring value =                        (jstring)env->GetObjectArrayElement(str_array, 1);                    const char *c_value =env->GetStringUTFChars(value, NULL);                    if (!strncmp(c_value,"true", strlen("true")))                        nat->adapter =get_adapter_path(nat->conn);                   env->ReleaseStringUTFChars(value, c_value);                }               env->ReleaseStringUTFChars(property, c_property);    //extra1.6调用对应的method_onPropertyChanged函数，该method对应的onPropertyChanged函数                env->CallVoidMethod(nat->me,                                 method_onPropertyChanged,                                  str_array);            } elseLOG_AND_FREE_DBUS_ERROR_WITH_MSG(&err, msg);            goto success;    ……         extra1.6真正的处理函数onPropertyChanged分析          /**         * Called by native code on aPropertyChanged signal from         * org.bluez.Adapter. This method is alsocalled from         * {@link BluetoothAdapterStateMachine} toset the "Pairable"         * property when Bluetooth is enabled.         *         * @param propValues a string arraycontaining the key and one or more         * values.         */        /*package*/ void onPropertyChanged(String[]propValues) {            BluetoothAdapterPropertiesadapterProperties =                   mBluetoothService.getAdapterProperties();    //先fill up cache            if (adapterProperties.isEmpty()) {                // We have got a property changebefore                // we filled up our cache.               adapterProperties.getAllProperties();            }            log("Property Changed: " +propValues[0] + " : " + propValues[1]);            String name = propValues[0];    ……    //对UUIDs的处理            } else if(name.equals("Devices") || name.equals("UUIDs")) {                String value = null;                int len =Integer.valueOf(propValues[1]);                if (len > 0) {                    StringBuilder str = newStringBuilder();                    for (int i = 2; i <propValues.length; i++) {                        str.append(propValues[i]);                        str.append(",");                    }                    value = str.toString();                }    //把name和value值加入到property的map中                adapterProperties.setProperty(name,value);    //extra1.7有UUIDs的change signal会刷新Bluetooth的State                if (name.equals("UUIDs")){                   mBluetoothService.updateBluetoothState(value);                }    //对Pairable和Discoverable的处理           } else if(name.equals("Pairable") || name.equals("Discoverable")) {                adapterProperties.setProperty(name,propValues[1]);                     if(name.equals("Discoverable")) {       //5.6发送SCAN_MODE_CHANGED的msg，去改变状态机      mBluetoothState.sendMessage(BluetoothAdapterStateMachine.SCAN_MODE_CHANGED);                }    //设置对应的property                String pairable =name.equals("Pairable") ? propValues[1] :                   adapterProperties.getProperty("Pairable");                String discoverable =name.equals("Discoverable") ? propValues[1] :                   adapterProperties.getProperty("Discoverable");                     // This shouldn't happen, unlessAdapter Properties are null.                if (pairable == null ||discoverable == null)                    return;                     int mode =BluetoothService.bluezStringToScanMode(                       pairable.equals("true"),                       discoverable.equals("true"));                if (mode >= 0) {    //当pairable和discoverable均为true的时候，会发送一个ACTION_SCAN_MODE_CHANGED的广播消息                    Intent intent = newIntent(BluetoothAdapter.ACTION_SCAN_MODE_CHANGED);                   intent.putExtra(BluetoothAdapter.EXTRA_SCAN_MODE, mode);                   intent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT);                    mContext.sendBroadcast(intent,BLUETOOTH_PERM);                }            }         ……         extra1.7  UUIDs改变带来的State的刷新             /**         * This function is called from BluetoothEvent Loop when onPropertyChanged         * for adapter comes in with UUID property.         * @param uuidsThe uuids of adapter asreported by Bluez.         */        /*package*/ synchronized voidupdateBluetoothState(String uuids) {            ParcelUuid[] adapterUuids =convertStringToParcelUuid(uuids);    //为什么必须包含所有已经有的uuid？？感觉有点反了，再看看            if (mAdapterUuids != null &&               BluetoothUuid.containsAllUuids(adapterUuids, mAdapterUuids)) {    //放SERVICE_RECORD_LOADED的信息，此时，处于warm up状态，看extra1.8分析状态如何继续改变          mBluetoothState.sendMessage(BluetoothAdapterStateMachine.SERVICE_RECORD_LOADED);            }        }         extra1.8 UUIDs对状态机改变            /**         * Turning on Bluetooth module's power,loading firmware, starting         * event loop thread to listen on Bluetoothmodule event changes.         */        private class WarmUp extends State {                 @Override            public void enter() {                if (DBG) log("Enter WarmUp:" + getCurrentMessage().what);            }                 @Override            public boolean processMessage(Messagemessage) {                log("WarmUp process message:" + message.what);                     boolean retValue = HANDLED;                switch(message.what) {                    case SERVICE_RECORD_LOADED:    //可以看到，首先会把当时从poweroff过来的一个超时message拿remove了。                       removeMessages(PREPARE_BLUETOOTH_TIMEOUT);    //转到hotoff状态，在hotoff状态仍会接收到多个SERVICE_RECORD_LOADED的msg，但是那个状态下该msg将没有任何handled，因此会一直处于hotoff状态                        transitionTo(mHotOff);                        break;    ……         5.2mAdapter.enable中mBluetoothState.sendMessage后的状态机处理         由extra的分析可知，此时，Bluetooth的State已经处于HotOff状态了，所以，从这里开始处理State的变换。             /**         * Bluetooth Module has powered, firmwareloaded, event loop started,         * SDP loaded, but the modules staysnon-discoverable and         * non-connectable.         */        private class HotOff extends State {            @Override            public void enter() {                if (DBG) log("Enter HotOff:" + getCurrentMessage().what);            }                 @Override            public boolean processMessage(Messagemessage) {                log("HotOff process message:" + message.what);                     boolean retValue = HANDLED;                switch(message.what) {                    case USER_TURN_ON:    //发出BluetoothAdapter.STATE_TURNING_ON的广播消息                       broadcastState(BluetoothAdapter.STATE_TURNING_ON);                        if ((Boolean) message.obj){    //就是把Settings.Secure.BLUETOOTH_ON设为1。用于标志Bluetooth enable了                           persistSwitchSetting(true);                        }                        // let it fall toTURN_ON_CONTINUE:                        //$FALL-THROUGH$    //注意上面没有break哦                    case TURN_ON_CONTINUE:    //这里就是把Bluetooth设为connectable就是Powered=1，这里就把prepareBluetooth中设置的不可连接重新设置回来了。这个重连会产生一些新的变化，它会发送WRITE_SCAN_ENABLE的cmd，因此在该cmd_complete时会有一些新的处理：5.3，它会再次引起状态机的改变：5.6                       mBluetoothService.switchConnectable(true);    //进入到Switching状态                        transitionTo(mSwitching);                        break;    ……         5.3 WRITE_SCAN_ENABLE在cmd_complete后的处理         在bluez中是用cmd_complete函数来监视发出cmd完成后的处理的。该函数具体如下：         staticinline void cmd_complete(int index, void *ptr)    {    structdev_info *dev = &devs[index];    evt_cmd_complete*evt = ptr;    uint16_topcode = btohs(evt->opcode);    uint8_tstatus = *((uint8_t *) ptr + EVT_CMD_COMPLETE_SIZE);         switch(opcode) {    ……    //WRITE_SCAN_ENABLE命令完成的处理函数，会再发一个READ_SCAN_ENABLE的命令    casecmd_opcode_pack(OGF_HOST_CTL, OCF_WRITE_SCAN_ENABLE):    hci_send_cmd(dev->sk,OGF_HOST_CTL, OCF_READ_SCAN_ENABLE,    0,NULL);    break;    //5.4紧接着就是对READ_SCAN_ENABLE命令完成的处理，它是通过read_scan_complete来实现的    casecmd_opcode_pack(OGF_HOST_CTL, OCF_READ_SCAN_ENABLE):    ptr+= sizeof(evt_cmd_complete);    read_scan_complete(index,status, ptr);    break;    ……    }         5.4 read_scan命令完成的处理         staticvoid read_scan_complete(int index, uint8_t status, void *ptr)    {    structbtd_adapter *adapter;    read_scan_enable_rp*rp = ptr;         DBG("hci%dstatus %u", index, status);    //由index得到对应的adapter    adapter= manager_find_adapter_by_id(index);    if(!adapter) {    error("Unableto find matching adapter");    return;    }    //5.5这里算是一个通知adapter，mode改变了。    adapter_mode_changed(adapter,rp->enable);    }         5.5通知adapter，mode发生了改变         voidadapter_mode_changed(struct btd_adapter *adapter, uint8_t scan_mode)    {    constgchar *path = adapter_get_path(adapter);    gbooleandiscoverable, pairable;         DBG("old0x%02x new 0x%02x", adapter->scan_mode, scan_mode);    //若相同，则nothing todo    if(adapter->scan_mode == scan_mode){    #ifdefBOARD_HAVE_BLUETOOTH_BCM        /*we may reset scan_mode already inbtd_adapter_stop(), so comes to here*/        set_mode_complete(adapter);    #endif        return;    }    //把discoverable的timeout清空    adapter_remove_discov_timeout(adapter);    //这里开始，是设为SCAN_PAGE| SCAN_INQUIRY    switch(scan_mode) {    caseSCAN_DISABLED:    adapter->mode= MODE_OFF;    discoverable= FALSE;    pairable= FALSE;    break;    caseSCAN_PAGE:    adapter->mode= MODE_CONNECTABLE;    discoverable= FALSE;    pairable= adapter->pairable;    break;    case(SCAN_PAGE | SCAN_INQUIRY):    //设一下模式，在有reply要求的情况下，该步骤还是很重要的    adapter->mode= MODE_DISCOVERABLE;    discoverable= TRUE;    pairable= adapter->pairable;    //还要设一个discoverable的时间    if(adapter->discov_timeout != 0)    adapter_set_discov_timeout(adapter,    adapter->discov_timeout);    break;    caseSCAN_INQUIRY:    /*Address the scenario where a low-level application like     * hciconfig changed the scan mode */    if(adapter->discov_timeout != 0)    adapter_set_discov_timeout(adapter,    adapter->discov_timeout);         /*ignore, this event should not be sent */    default:    /*ignore, reserved */    return;    }         /*If page scanning gets toggled emit the Pairable property */    //这里会发一个property_changed的pairable的signal    if((adapter->scan_mode & SCAN_PAGE) != (scan_mode & SCAN_PAGE))    emit_property_changed(connection,adapter->path,    ADAPTER_INTERFACE,"Pairable",    DBUS_TYPE_BOOLEAN,&pairable);         if(!discoverable)    adapter_set_limited_discoverable(adapter,FALSE);    //这里会发一个property_changed的discoverable的signal    emit_property_changed(connection,path,    ADAPTER_INTERFACE,"Discoverable",    DBUS_TYPE_BOOLEAN,&discoverable);    adapter->scan_mode= scan_mode;         set_mode_complete(adapter);    }

5.6 WRTIE_SCAN_ENABLE最终引起的状态机的变化

在此之前，状态机处于switching的状态，收到了SCAN_MODE_CHANGED的msg。

    private class Switching extends State {                 @Override            public void enter() {                if (DBG) log("Enter Switching:" + getCurrentMessage().what);            }            @Override            public boolean processMessage(Messagemessage) {                log("Switching processmessage: " + message.what);                     boolean retValue = HANDLED;                switch(message.what) {                    case SCAN_MODE_CHANGED:                        // This event matchesmBluetoothService.switchConnectable action    //mPublicState在hotoff到swtiching状态变化时已经被设为STATE_TURNING_ON了，所以这里if没有问题                        if (mPublicState ==BluetoothAdapter.STATE_TURNING_ON) {                            // set pairable if it'snot    //设置为pairable假如还没有设置的话，这个会先在bluez中检查一下当前是否pairable，我们在前面已经设置好了，所以，这里只是一个检查而已，没有什么实际性的工作                           mBluetoothService.setPairable();    //初始化bond state和profile state，这个会在adapter pairable之后，bluetooth turn on之前发生                           mBluetoothService.initBluetoothAfterTurningOn();    //这边正式进入到bluetoothon的状态，终于进了这里，哎。。。                           transitionTo(mBluetoothOn);    //发送STATE_ON的broadcast                           broadcastState(BluetoothAdapter.STATE_ON);                            // run bluetooth nowthat it's turned on                            // Note runBluetoothshould be called only in adapter STATE_ON    //连接那些可以自动连接的设备，通知battery，蓝牙打开了                           mBluetoothService.runBluetooth();                        }                        break;    ……

至此，蓝牙的使能主要过程已经全部搞定。

原文地址：http://blog.csdn.net/xdyang1987/article/details/7771388